Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
bf2c59fc | 6 | #include <linux/sched/mm.h> |
1da177e4 LT |
7 | #include <linux/proc_fs.h> |
8 | #include <linux/smp.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/notifier.h> | |
3f07c014 | 11 | #include <linux/sched/signal.h> |
ef8bd77f | 12 | #include <linux/sched/hotplug.h> |
9ca12ac0 | 13 | #include <linux/sched/isolation.h> |
29930025 | 14 | #include <linux/sched/task.h> |
a74cfffb | 15 | #include <linux/sched/smt.h> |
1da177e4 LT |
16 | #include <linux/unistd.h> |
17 | #include <linux/cpu.h> | |
cb79295e AV |
18 | #include <linux/oom.h> |
19 | #include <linux/rcupdate.h> | |
9984de1a | 20 | #include <linux/export.h> |
e4cc2f87 | 21 | #include <linux/bug.h> |
1da177e4 LT |
22 | #include <linux/kthread.h> |
23 | #include <linux/stop_machine.h> | |
81615b62 | 24 | #include <linux/mutex.h> |
5a0e3ad6 | 25 | #include <linux/gfp.h> |
79cfbdfa | 26 | #include <linux/suspend.h> |
a19423b9 | 27 | #include <linux/lockdep.h> |
345527b1 | 28 | #include <linux/tick.h> |
a8994181 | 29 | #include <linux/irq.h> |
941154bd | 30 | #include <linux/nmi.h> |
4cb28ced | 31 | #include <linux/smpboot.h> |
e6d4989a | 32 | #include <linux/relay.h> |
6731d4f1 | 33 | #include <linux/slab.h> |
fc8dffd3 | 34 | #include <linux/percpu-rwsem.h> |
b22afcdf | 35 | #include <linux/cpuset.h> |
cff7d378 | 36 | |
bb3632c6 | 37 | #include <trace/events/power.h> |
cff7d378 TG |
38 | #define CREATE_TRACE_POINTS |
39 | #include <trace/events/cpuhp.h> | |
1da177e4 | 40 | |
38498a67 TG |
41 | #include "smpboot.h" |
42 | ||
cff7d378 TG |
43 | /** |
44 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
45 | * @state: The current cpu state | |
46 | * @target: The target state | |
4cb28ced TG |
47 | * @thread: Pointer to the hotplug thread |
48 | * @should_run: Thread should execute | |
3b9d6da6 | 49 | * @rollback: Perform a rollback |
a724632c TG |
50 | * @single: Single callback invocation |
51 | * @bringup: Single callback bringup or teardown selector | |
52 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 53 | * @result: Result of the operation |
5ebe7742 PZ |
54 | * @done_up: Signal completion to the issuer of the task for cpu-up |
55 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
56 | */ |
57 | struct cpuhp_cpu_state { | |
58 | enum cpuhp_state state; | |
59 | enum cpuhp_state target; | |
1db49484 | 60 | enum cpuhp_state fail; |
4cb28ced TG |
61 | #ifdef CONFIG_SMP |
62 | struct task_struct *thread; | |
63 | bool should_run; | |
3b9d6da6 | 64 | bool rollback; |
a724632c TG |
65 | bool single; |
66 | bool bringup; | |
2ea46c6f | 67 | int cpu; |
cf392d10 | 68 | struct hlist_node *node; |
4dddfb5f | 69 | struct hlist_node *last; |
4cb28ced | 70 | enum cpuhp_state cb_state; |
4cb28ced | 71 | int result; |
5ebe7742 PZ |
72 | struct completion done_up; |
73 | struct completion done_down; | |
4cb28ced | 74 | #endif |
cff7d378 TG |
75 | }; |
76 | ||
1db49484 PZ |
77 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
78 | .fail = CPUHP_INVALID, | |
79 | }; | |
cff7d378 | 80 | |
e797bda3 TG |
81 | #ifdef CONFIG_SMP |
82 | cpumask_t cpus_booted_once_mask; | |
83 | #endif | |
84 | ||
49dfe2a6 | 85 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
86 | static struct lockdep_map cpuhp_state_up_map = |
87 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
88 | static struct lockdep_map cpuhp_state_down_map = | |
89 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
90 | ||
91 | ||
76dc6c09 | 92 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
93 | { |
94 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
95 | } | |
96 | ||
76dc6c09 | 97 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
98 | { |
99 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
100 | } | |
101 | #else | |
102 | ||
76dc6c09 MM |
103 | static inline void cpuhp_lock_acquire(bool bringup) { } |
104 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 105 | |
49dfe2a6 TG |
106 | #endif |
107 | ||
cff7d378 TG |
108 | /** |
109 | * cpuhp_step - Hotplug state machine step | |
110 | * @name: Name of the step | |
111 | * @startup: Startup function of the step | |
112 | * @teardown: Teardown function of the step | |
757c989b | 113 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
114 | */ |
115 | struct cpuhp_step { | |
cf392d10 TG |
116 | const char *name; |
117 | union { | |
3c1627e9 TG |
118 | int (*single)(unsigned int cpu); |
119 | int (*multi)(unsigned int cpu, | |
120 | struct hlist_node *node); | |
121 | } startup; | |
cf392d10 | 122 | union { |
3c1627e9 TG |
123 | int (*single)(unsigned int cpu); |
124 | int (*multi)(unsigned int cpu, | |
125 | struct hlist_node *node); | |
126 | } teardown; | |
cf392d10 | 127 | struct hlist_head list; |
cf392d10 TG |
128 | bool cant_stop; |
129 | bool multi_instance; | |
cff7d378 TG |
130 | }; |
131 | ||
98f8cdce | 132 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 133 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 134 | |
a724632c TG |
135 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
136 | { | |
17a2f1ce | 137 | return cpuhp_hp_states + state; |
a724632c TG |
138 | } |
139 | ||
453e4108 VD |
140 | static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step) |
141 | { | |
142 | return bringup ? !step->startup.single : !step->teardown.single; | |
143 | } | |
144 | ||
cff7d378 TG |
145 | /** |
146 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
147 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 148 | * @state: The state to do callbacks for |
a724632c | 149 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
150 | * @node: For multi-instance, do a single entry callback for install/remove |
151 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 152 | * |
cf392d10 | 153 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 154 | */ |
a724632c | 155 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
156 | bool bringup, struct hlist_node *node, |
157 | struct hlist_node **lastp) | |
cff7d378 TG |
158 | { |
159 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 160 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
161 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
162 | int (*cb)(unsigned int cpu); | |
163 | int ret, cnt; | |
164 | ||
1db49484 PZ |
165 | if (st->fail == state) { |
166 | st->fail = CPUHP_INVALID; | |
1db49484 PZ |
167 | return -EAGAIN; |
168 | } | |
169 | ||
453e4108 VD |
170 | if (cpuhp_step_empty(bringup, step)) { |
171 | WARN_ON_ONCE(1); | |
172 | return 0; | |
173 | } | |
174 | ||
cf392d10 | 175 | if (!step->multi_instance) { |
96abb968 | 176 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 177 | cb = bringup ? step->startup.single : step->teardown.single; |
453e4108 | 178 | |
a724632c | 179 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 180 | ret = cb(cpu); |
a724632c | 181 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
182 | return ret; |
183 | } | |
3c1627e9 | 184 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
185 | |
186 | /* Single invocation for instance add/remove */ | |
187 | if (node) { | |
96abb968 | 188 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
189 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
190 | ret = cbm(cpu, node); | |
191 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
192 | return ret; | |
193 | } | |
194 | ||
195 | /* State transition. Invoke on all instances */ | |
196 | cnt = 0; | |
197 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
198 | if (lastp && node == *lastp) |
199 | break; | |
200 | ||
cf392d10 TG |
201 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
202 | ret = cbm(cpu, node); | |
203 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
204 | if (ret) { |
205 | if (!lastp) | |
206 | goto err; | |
207 | ||
208 | *lastp = node; | |
209 | return ret; | |
210 | } | |
cf392d10 TG |
211 | cnt++; |
212 | } | |
96abb968 PZ |
213 | if (lastp) |
214 | *lastp = NULL; | |
cf392d10 TG |
215 | return 0; |
216 | err: | |
217 | /* Rollback the instances if one failed */ | |
3c1627e9 | 218 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
219 | if (!cbm) |
220 | return ret; | |
221 | ||
222 | hlist_for_each(node, &step->list) { | |
223 | if (!cnt--) | |
224 | break; | |
724a8688 PZ |
225 | |
226 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
227 | ret = cbm(cpu, node); | |
228 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
229 | /* | |
230 | * Rollback must not fail, | |
231 | */ | |
232 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
233 | } |
234 | return ret; | |
235 | } | |
236 | ||
98a79d6a | 237 | #ifdef CONFIG_SMP |
fcb3029a AB |
238 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
239 | { | |
240 | /* | |
241 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
242 | * purposes as that state is handled explicitly in cpu_down. | |
243 | */ | |
244 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
245 | } | |
246 | ||
5ebe7742 PZ |
247 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
248 | { | |
249 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
250 | wait_for_completion(done); | |
251 | } | |
252 | ||
253 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
254 | { | |
255 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
256 | complete(done); | |
257 | } | |
258 | ||
259 | /* | |
260 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
261 | */ | |
262 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
263 | { | |
264 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
265 | } | |
266 | ||
b3199c02 | 267 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 268 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
269 | bool cpuhp_tasks_frozen; |
270 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 271 | |
79a6cdeb | 272 | /* |
93ae4f97 SB |
273 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
274 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
275 | */ |
276 | void cpu_maps_update_begin(void) | |
277 | { | |
278 | mutex_lock(&cpu_add_remove_lock); | |
279 | } | |
280 | ||
281 | void cpu_maps_update_done(void) | |
282 | { | |
283 | mutex_unlock(&cpu_add_remove_lock); | |
284 | } | |
1da177e4 | 285 | |
fc8dffd3 TG |
286 | /* |
287 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
288 | * Should always be manipulated under cpu_add_remove_lock |
289 | */ | |
290 | static int cpu_hotplug_disabled; | |
291 | ||
79a6cdeb LJ |
292 | #ifdef CONFIG_HOTPLUG_CPU |
293 | ||
fc8dffd3 | 294 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 295 | |
8f553c49 | 296 | void cpus_read_lock(void) |
a9d9baa1 | 297 | { |
fc8dffd3 | 298 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 299 | } |
8f553c49 | 300 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 301 | |
6f4ceee9 WL |
302 | int cpus_read_trylock(void) |
303 | { | |
304 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
305 | } | |
306 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
307 | ||
8f553c49 | 308 | void cpus_read_unlock(void) |
a9d9baa1 | 309 | { |
fc8dffd3 | 310 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 311 | } |
8f553c49 | 312 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 313 | |
8f553c49 | 314 | void cpus_write_lock(void) |
d221938c | 315 | { |
fc8dffd3 | 316 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 317 | } |
87af9e7f | 318 | |
8f553c49 | 319 | void cpus_write_unlock(void) |
d221938c | 320 | { |
fc8dffd3 | 321 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
322 | } |
323 | ||
fc8dffd3 | 324 | void lockdep_assert_cpus_held(void) |
d221938c | 325 | { |
ce48c457 VS |
326 | /* |
327 | * We can't have hotplug operations before userspace starts running, | |
328 | * and some init codepaths will knowingly not take the hotplug lock. | |
329 | * This is all valid, so mute lockdep until it makes sense to report | |
330 | * unheld locks. | |
331 | */ | |
332 | if (system_state < SYSTEM_RUNNING) | |
333 | return; | |
334 | ||
fc8dffd3 | 335 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 336 | } |
79a6cdeb | 337 | |
43759fe5 FW |
338 | #ifdef CONFIG_LOCKDEP |
339 | int lockdep_is_cpus_held(void) | |
340 | { | |
341 | return percpu_rwsem_is_held(&cpu_hotplug_lock); | |
342 | } | |
343 | #endif | |
344 | ||
cb92173d PZ |
345 | static void lockdep_acquire_cpus_lock(void) |
346 | { | |
1751060e | 347 | rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); |
cb92173d PZ |
348 | } |
349 | ||
350 | static void lockdep_release_cpus_lock(void) | |
351 | { | |
1751060e | 352 | rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); |
cb92173d PZ |
353 | } |
354 | ||
16e53dbf SB |
355 | /* |
356 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
357 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
358 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
359 | * hotplug path before performing hotplug operations. So acquiring that lock | |
360 | * guarantees mutual exclusion from any currently running hotplug operations. | |
361 | */ | |
362 | void cpu_hotplug_disable(void) | |
363 | { | |
364 | cpu_maps_update_begin(); | |
89af7ba5 | 365 | cpu_hotplug_disabled++; |
16e53dbf SB |
366 | cpu_maps_update_done(); |
367 | } | |
32145c46 | 368 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 369 | |
01b41159 LW |
370 | static void __cpu_hotplug_enable(void) |
371 | { | |
372 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
373 | return; | |
374 | cpu_hotplug_disabled--; | |
375 | } | |
376 | ||
16e53dbf SB |
377 | void cpu_hotplug_enable(void) |
378 | { | |
379 | cpu_maps_update_begin(); | |
01b41159 | 380 | __cpu_hotplug_enable(); |
16e53dbf SB |
381 | cpu_maps_update_done(); |
382 | } | |
32145c46 | 383 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
384 | |
385 | #else | |
386 | ||
387 | static void lockdep_acquire_cpus_lock(void) | |
388 | { | |
389 | } | |
390 | ||
391 | static void lockdep_release_cpus_lock(void) | |
392 | { | |
393 | } | |
394 | ||
b9d10be7 | 395 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 396 | |
a74cfffb TG |
397 | /* |
398 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
399 | * should override this. | |
400 | */ | |
401 | void __weak arch_smt_update(void) { } | |
402 | ||
0cc3cd21 TG |
403 | #ifdef CONFIG_HOTPLUG_SMT |
404 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 405 | |
8e1b706b | 406 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 407 | { |
e1572f1d | 408 | if (!cpu_smt_possible()) |
8e1b706b JK |
409 | return; |
410 | ||
411 | if (force) { | |
0cc3cd21 TG |
412 | pr_info("SMT: Force disabled\n"); |
413 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 414 | } else { |
d0e7d144 | 415 | pr_info("SMT: disabled\n"); |
8e1b706b | 416 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 417 | } |
8e1b706b JK |
418 | } |
419 | ||
fee0aede TG |
420 | /* |
421 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 422 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
423 | */ |
424 | void __init cpu_smt_check_topology(void) | |
425 | { | |
b284909a | 426 | if (!topology_smt_supported()) |
bc2d8d26 TG |
427 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
428 | } | |
429 | ||
8e1b706b JK |
430 | static int __init smt_cmdline_disable(char *str) |
431 | { | |
432 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
433 | return 0; |
434 | } | |
435 | early_param("nosmt", smt_cmdline_disable); | |
436 | ||
437 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
438 | { | |
b284909a | 439 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
440 | return true; |
441 | ||
b284909a | 442 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
443 | return true; |
444 | ||
445 | /* | |
446 | * On x86 it's required to boot all logical CPUs at least once so | |
447 | * that the init code can get a chance to set CR4.MCE on each | |
182e073f | 448 | * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any |
0cc3cd21 TG |
449 | * core will shutdown the machine. |
450 | */ | |
e797bda3 | 451 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 452 | } |
e1572f1d VK |
453 | |
454 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
455 | bool cpu_smt_possible(void) | |
456 | { | |
457 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
458 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
459 | } | |
460 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
461 | #else |
462 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
463 | #endif | |
464 | ||
4dddfb5f PZ |
465 | static inline enum cpuhp_state |
466 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
467 | { | |
468 | enum cpuhp_state prev_state = st->state; | |
2ea46c6f | 469 | bool bringup = st->state < target; |
4dddfb5f PZ |
470 | |
471 | st->rollback = false; | |
472 | st->last = NULL; | |
473 | ||
474 | st->target = target; | |
475 | st->single = false; | |
2ea46c6f PZ |
476 | st->bringup = bringup; |
477 | if (cpu_dying(st->cpu) != !bringup) | |
478 | set_cpu_dying(st->cpu, !bringup); | |
4dddfb5f PZ |
479 | |
480 | return prev_state; | |
481 | } | |
482 | ||
483 | static inline void | |
484 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
485 | { | |
2ea46c6f PZ |
486 | bool bringup = !st->bringup; |
487 | ||
453e4108 VD |
488 | st->target = prev_state; |
489 | ||
490 | /* | |
491 | * Already rolling back. No need invert the bringup value or to change | |
492 | * the current state. | |
493 | */ | |
494 | if (st->rollback) | |
495 | return; | |
496 | ||
4dddfb5f PZ |
497 | st->rollback = true; |
498 | ||
499 | /* | |
500 | * If we have st->last we need to undo partial multi_instance of this | |
501 | * state first. Otherwise start undo at the previous state. | |
502 | */ | |
503 | if (!st->last) { | |
504 | if (st->bringup) | |
505 | st->state--; | |
506 | else | |
507 | st->state++; | |
508 | } | |
509 | ||
2ea46c6f PZ |
510 | st->bringup = bringup; |
511 | if (cpu_dying(st->cpu) != !bringup) | |
512 | set_cpu_dying(st->cpu, !bringup); | |
4dddfb5f PZ |
513 | } |
514 | ||
515 | /* Regular hotplug invocation of the AP hotplug thread */ | |
516 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
517 | { | |
518 | if (!st->single && st->state == st->target) | |
519 | return; | |
520 | ||
521 | st->result = 0; | |
522 | /* | |
523 | * Make sure the above stores are visible before should_run becomes | |
524 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
525 | */ | |
526 | smp_mb(); | |
527 | st->should_run = true; | |
528 | wake_up_process(st->thread); | |
5ebe7742 | 529 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
530 | } |
531 | ||
532 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
533 | { | |
534 | enum cpuhp_state prev_state; | |
535 | int ret; | |
536 | ||
537 | prev_state = cpuhp_set_state(st, target); | |
538 | __cpuhp_kick_ap(st); | |
539 | if ((ret = st->result)) { | |
540 | cpuhp_reset_state(st, prev_state); | |
541 | __cpuhp_kick_ap(st); | |
542 | } | |
543 | ||
544 | return ret; | |
545 | } | |
9cd4f1a4 | 546 | |
8df3e07e TG |
547 | static int bringup_wait_for_ap(unsigned int cpu) |
548 | { | |
549 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
550 | ||
9cd4f1a4 | 551 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 552 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
553 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
554 | return -ECANCELED; | |
9cd4f1a4 | 555 | |
45178ac0 | 556 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
557 | kthread_unpark(st->thread); |
558 | ||
0cc3cd21 TG |
559 | /* |
560 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
561 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 562 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
563 | * cpu_smt_allowed() check will now return false if this is not the |
564 | * primary sibling. | |
565 | */ | |
566 | if (!cpu_smt_allowed(cpu)) | |
567 | return -ECANCELED; | |
568 | ||
4dddfb5f PZ |
569 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
570 | return 0; | |
571 | ||
572 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
573 | } |
574 | ||
ba997462 TG |
575 | static int bringup_cpu(unsigned int cpu) |
576 | { | |
577 | struct task_struct *idle = idle_thread_get(cpu); | |
578 | int ret; | |
579 | ||
aa877175 BO |
580 | /* |
581 | * Some architectures have to walk the irq descriptors to | |
582 | * setup the vector space for the cpu which comes online. | |
583 | * Prevent irq alloc/free across the bringup. | |
584 | */ | |
585 | irq_lock_sparse(); | |
586 | ||
ba997462 TG |
587 | /* Arch-specific enabling code. */ |
588 | ret = __cpu_up(cpu, idle); | |
aa877175 | 589 | irq_unlock_sparse(); |
530e9b76 | 590 | if (ret) |
ba997462 | 591 | return ret; |
9cd4f1a4 | 592 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
593 | } |
594 | ||
bf2c59fc PZ |
595 | static int finish_cpu(unsigned int cpu) |
596 | { | |
597 | struct task_struct *idle = idle_thread_get(cpu); | |
598 | struct mm_struct *mm = idle->active_mm; | |
599 | ||
600 | /* | |
601 | * idle_task_exit() will have switched to &init_mm, now | |
602 | * clean up any remaining active_mm state. | |
603 | */ | |
604 | if (mm != &init_mm) | |
605 | idle->active_mm = &init_mm; | |
606 | mmdrop(mm); | |
607 | return 0; | |
608 | } | |
609 | ||
2e1a3483 TG |
610 | /* |
611 | * Hotplug state machine related functions | |
612 | */ | |
2e1a3483 | 613 | |
453e4108 VD |
614 | /* |
615 | * Get the next state to run. Empty ones will be skipped. Returns true if a | |
616 | * state must be run. | |
617 | * | |
618 | * st->state will be modified ahead of time, to match state_to_run, as if it | |
619 | * has already ran. | |
620 | */ | |
621 | static bool cpuhp_next_state(bool bringup, | |
622 | enum cpuhp_state *state_to_run, | |
623 | struct cpuhp_cpu_state *st, | |
624 | enum cpuhp_state target) | |
2e1a3483 | 625 | { |
453e4108 VD |
626 | do { |
627 | if (bringup) { | |
628 | if (st->state >= target) | |
629 | return false; | |
630 | ||
631 | *state_to_run = ++st->state; | |
632 | } else { | |
633 | if (st->state <= target) | |
634 | return false; | |
635 | ||
636 | *state_to_run = st->state--; | |
637 | } | |
638 | ||
639 | if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run))) | |
640 | break; | |
641 | } while (true); | |
642 | ||
643 | return true; | |
644 | } | |
645 | ||
646 | static int cpuhp_invoke_callback_range(bool bringup, | |
647 | unsigned int cpu, | |
648 | struct cpuhp_cpu_state *st, | |
649 | enum cpuhp_state target) | |
650 | { | |
651 | enum cpuhp_state state; | |
652 | int err = 0; | |
653 | ||
654 | while (cpuhp_next_state(bringup, &state, st, target)) { | |
655 | err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL); | |
656 | if (err) | |
657 | break; | |
658 | } | |
659 | ||
660 | return err; | |
2e1a3483 TG |
661 | } |
662 | ||
206b9235 TG |
663 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
664 | { | |
665 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
666 | return true; | |
667 | /* | |
668 | * When CPU hotplug is disabled, then taking the CPU down is not | |
669 | * possible because takedown_cpu() and the architecture and | |
670 | * subsystem specific mechanisms are not available. So the CPU | |
671 | * which would be completely unplugged again needs to stay around | |
672 | * in the current state. | |
673 | */ | |
674 | return st->state <= CPUHP_BRINGUP_CPU; | |
675 | } | |
676 | ||
2e1a3483 | 677 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 678 | enum cpuhp_state target) |
2e1a3483 TG |
679 | { |
680 | enum cpuhp_state prev_state = st->state; | |
681 | int ret = 0; | |
682 | ||
453e4108 VD |
683 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
684 | if (ret) { | |
685 | cpuhp_reset_state(st, prev_state); | |
686 | if (can_rollback_cpu(st)) | |
687 | WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, | |
688 | prev_state)); | |
2e1a3483 TG |
689 | } |
690 | return ret; | |
691 | } | |
692 | ||
4cb28ced TG |
693 | /* |
694 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
695 | */ | |
696 | static void cpuhp_create(unsigned int cpu) | |
697 | { | |
698 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
699 | ||
5ebe7742 PZ |
700 | init_completion(&st->done_up); |
701 | init_completion(&st->done_down); | |
2ea46c6f | 702 | st->cpu = cpu; |
4cb28ced TG |
703 | } |
704 | ||
705 | static int cpuhp_should_run(unsigned int cpu) | |
706 | { | |
707 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
708 | ||
709 | return st->should_run; | |
710 | } | |
711 | ||
4cb28ced TG |
712 | /* |
713 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
714 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
715 | * |
716 | * Each invocation of this function by the smpboot thread does a single AP | |
717 | * state callback. | |
718 | * | |
719 | * It has 3 modes of operation: | |
720 | * - single: runs st->cb_state | |
721 | * - up: runs ++st->state, while st->state < st->target | |
722 | * - down: runs st->state--, while st->state > st->target | |
723 | * | |
724 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
725 | */ |
726 | static void cpuhp_thread_fun(unsigned int cpu) | |
727 | { | |
728 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
729 | bool bringup = st->bringup; |
730 | enum cpuhp_state state; | |
4cb28ced | 731 | |
f8b7530a NU |
732 | if (WARN_ON_ONCE(!st->should_run)) |
733 | return; | |
734 | ||
4cb28ced | 735 | /* |
4dddfb5f PZ |
736 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
737 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
738 | */ |
739 | smp_mb(); | |
4cb28ced | 740 | |
cb92173d PZ |
741 | /* |
742 | * The BP holds the hotplug lock, but we're now running on the AP, | |
743 | * ensure that anybody asserting the lock is held, will actually find | |
744 | * it so. | |
745 | */ | |
746 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 747 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 748 | |
a724632c | 749 | if (st->single) { |
4dddfb5f PZ |
750 | state = st->cb_state; |
751 | st->should_run = false; | |
752 | } else { | |
453e4108 VD |
753 | st->should_run = cpuhp_next_state(bringup, &state, st, st->target); |
754 | if (!st->should_run) | |
755 | goto end; | |
4dddfb5f PZ |
756 | } |
757 | ||
758 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
759 | ||
4dddfb5f PZ |
760 | if (cpuhp_is_atomic_state(state)) { |
761 | local_irq_disable(); | |
762 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
763 | local_irq_enable(); | |
3b9d6da6 | 764 | |
4dddfb5f PZ |
765 | /* |
766 | * STARTING/DYING must not fail! | |
767 | */ | |
768 | WARN_ON_ONCE(st->result); | |
4cb28ced | 769 | } else { |
4dddfb5f PZ |
770 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
771 | } | |
772 | ||
773 | if (st->result) { | |
774 | /* | |
775 | * If we fail on a rollback, we're up a creek without no | |
776 | * paddle, no way forward, no way back. We loose, thanks for | |
777 | * playing. | |
778 | */ | |
779 | WARN_ON_ONCE(st->rollback); | |
780 | st->should_run = false; | |
4cb28ced | 781 | } |
4dddfb5f | 782 | |
453e4108 | 783 | end: |
5f4b55e1 | 784 | cpuhp_lock_release(bringup); |
cb92173d | 785 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
786 | |
787 | if (!st->should_run) | |
5ebe7742 | 788 | complete_ap_thread(st, bringup); |
4cb28ced TG |
789 | } |
790 | ||
791 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 792 | static int |
cf392d10 TG |
793 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
794 | struct hlist_node *node) | |
4cb28ced TG |
795 | { |
796 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 797 | int ret; |
4cb28ced TG |
798 | |
799 | if (!cpu_online(cpu)) | |
800 | return 0; | |
801 | ||
5f4b55e1 PZ |
802 | cpuhp_lock_acquire(false); |
803 | cpuhp_lock_release(false); | |
804 | ||
805 | cpuhp_lock_acquire(true); | |
806 | cpuhp_lock_release(true); | |
49dfe2a6 | 807 | |
6a4e2451 TG |
808 | /* |
809 | * If we are up and running, use the hotplug thread. For early calls | |
810 | * we invoke the thread function directly. | |
811 | */ | |
812 | if (!st->thread) | |
96abb968 | 813 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 814 | |
4dddfb5f PZ |
815 | st->rollback = false; |
816 | st->last = NULL; | |
817 | ||
818 | st->node = node; | |
819 | st->bringup = bringup; | |
4cb28ced | 820 | st->cb_state = state; |
a724632c | 821 | st->single = true; |
a724632c | 822 | |
4dddfb5f | 823 | __cpuhp_kick_ap(st); |
4cb28ced | 824 | |
4cb28ced | 825 | /* |
4dddfb5f | 826 | * If we failed and did a partial, do a rollback. |
4cb28ced | 827 | */ |
4dddfb5f PZ |
828 | if ((ret = st->result) && st->last) { |
829 | st->rollback = true; | |
830 | st->bringup = !bringup; | |
831 | ||
832 | __cpuhp_kick_ap(st); | |
833 | } | |
834 | ||
1f7c70d6 TG |
835 | /* |
836 | * Clean up the leftovers so the next hotplug operation wont use stale | |
837 | * data. | |
838 | */ | |
839 | st->node = st->last = NULL; | |
4dddfb5f | 840 | return ret; |
1cf4f629 TG |
841 | } |
842 | ||
843 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
844 | { | |
845 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
846 | enum cpuhp_state prev_state = st->state; |
847 | int ret; | |
1cf4f629 | 848 | |
5f4b55e1 PZ |
849 | cpuhp_lock_acquire(false); |
850 | cpuhp_lock_release(false); | |
851 | ||
852 | cpuhp_lock_acquire(true); | |
853 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
854 | |
855 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
856 | ret = cpuhp_kick_ap(st, st->target); | |
857 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
858 | ||
859 | return ret; | |
4cb28ced TG |
860 | } |
861 | ||
862 | static struct smp_hotplug_thread cpuhp_threads = { | |
863 | .store = &cpuhp_state.thread, | |
864 | .create = &cpuhp_create, | |
865 | .thread_should_run = cpuhp_should_run, | |
866 | .thread_fn = cpuhp_thread_fun, | |
867 | .thread_comm = "cpuhp/%u", | |
868 | .selfparking = true, | |
869 | }; | |
870 | ||
871 | void __init cpuhp_threads_init(void) | |
872 | { | |
873 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
874 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
875 | } | |
876 | ||
b22afcdf TG |
877 | /* |
878 | * | |
879 | * Serialize hotplug trainwrecks outside of the cpu_hotplug_lock | |
880 | * protected region. | |
881 | * | |
882 | * The operation is still serialized against concurrent CPU hotplug via | |
883 | * cpu_add_remove_lock, i.e. CPU map protection. But it is _not_ | |
884 | * serialized against other hotplug related activity like adding or | |
885 | * removing of state callbacks and state instances, which invoke either the | |
886 | * startup or the teardown callback of the affected state. | |
887 | * | |
888 | * This is required for subsystems which are unfixable vs. CPU hotplug and | |
889 | * evade lock inversion problems by scheduling work which has to be | |
890 | * completed _before_ cpu_up()/_cpu_down() returns. | |
891 | * | |
892 | * Don't even think about adding anything to this for any new code or even | |
893 | * drivers. It's only purpose is to keep existing lock order trainwrecks | |
894 | * working. | |
895 | * | |
896 | * For cpu_down() there might be valid reasons to finish cleanups which are | |
897 | * not required to be done under cpu_hotplug_lock, but that's a different | |
898 | * story and would be not invoked via this. | |
899 | */ | |
900 | static void cpu_up_down_serialize_trainwrecks(bool tasks_frozen) | |
901 | { | |
902 | /* | |
903 | * cpusets delegate hotplug operations to a worker to "solve" the | |
904 | * lock order problems. Wait for the worker, but only if tasks are | |
905 | * _not_ frozen (suspend, hibernate) as that would wait forever. | |
906 | * | |
907 | * The wait is required because otherwise the hotplug operation | |
908 | * returns with inconsistent state, which could even be observed in | |
909 | * user space when a new CPU is brought up. The CPU plug uevent | |
910 | * would be delivered and user space reacting on it would fail to | |
911 | * move tasks to the newly plugged CPU up to the point where the | |
912 | * work has finished because up to that point the newly plugged CPU | |
913 | * is not assignable in cpusets/cgroups. On unplug that's not | |
914 | * necessarily a visible issue, but it is still inconsistent state, | |
915 | * which is the real problem which needs to be "fixed". This can't | |
916 | * prevent the transient state between scheduling the work and | |
917 | * returning from waiting for it. | |
918 | */ | |
919 | if (!tasks_frozen) | |
920 | cpuset_wait_for_hotplug(); | |
921 | } | |
922 | ||
777c6e0d | 923 | #ifdef CONFIG_HOTPLUG_CPU |
8ff00399 NP |
924 | #ifndef arch_clear_mm_cpumask_cpu |
925 | #define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm)) | |
926 | #endif | |
927 | ||
e4cc2f87 AV |
928 | /** |
929 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
930 | * @cpu: a CPU id | |
931 | * | |
932 | * This function walks all processes, finds a valid mm struct for each one and | |
933 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
934 | * trivial, there are various non-obvious corner cases, which this function | |
935 | * tries to solve in a safe manner. | |
936 | * | |
937 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
938 | * be called only for an already offlined CPU. | |
939 | */ | |
cb79295e AV |
940 | void clear_tasks_mm_cpumask(int cpu) |
941 | { | |
942 | struct task_struct *p; | |
943 | ||
944 | /* | |
945 | * This function is called after the cpu is taken down and marked | |
946 | * offline, so its not like new tasks will ever get this cpu set in | |
947 | * their mm mask. -- Peter Zijlstra | |
948 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
949 | * full-fledged tasklist_lock. | |
950 | */ | |
e4cc2f87 | 951 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
952 | rcu_read_lock(); |
953 | for_each_process(p) { | |
954 | struct task_struct *t; | |
955 | ||
e4cc2f87 AV |
956 | /* |
957 | * Main thread might exit, but other threads may still have | |
958 | * a valid mm. Find one. | |
959 | */ | |
cb79295e AV |
960 | t = find_lock_task_mm(p); |
961 | if (!t) | |
962 | continue; | |
8ff00399 | 963 | arch_clear_mm_cpumask_cpu(cpu, t->mm); |
cb79295e AV |
964 | task_unlock(t); |
965 | } | |
966 | rcu_read_unlock(); | |
967 | } | |
968 | ||
1da177e4 | 969 | /* Take this CPU down. */ |
71cf5aee | 970 | static int take_cpu_down(void *_param) |
1da177e4 | 971 | { |
4baa0afc TG |
972 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
973 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 974 | int err, cpu = smp_processor_id(); |
724a8688 | 975 | int ret; |
1da177e4 | 976 | |
1da177e4 LT |
977 | /* Ensure this CPU doesn't handle any more interrupts. */ |
978 | err = __cpu_disable(); | |
979 | if (err < 0) | |
f3705136 | 980 | return err; |
1da177e4 | 981 | |
a724632c | 982 | /* |
453e4108 VD |
983 | * Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going |
984 | * down, that the current state is CPUHP_TEARDOWN_CPU - 1. | |
a724632c | 985 | */ |
453e4108 VD |
986 | WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1)); |
987 | ||
4baa0afc | 988 | /* Invoke the former CPU_DYING callbacks */ |
453e4108 VD |
989 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
990 | ||
991 | /* | |
992 | * DYING must not fail! | |
993 | */ | |
994 | WARN_ON_ONCE(ret); | |
4baa0afc | 995 | |
52c063d1 TG |
996 | /* Give up timekeeping duties */ |
997 | tick_handover_do_timer(); | |
1b72d432 TG |
998 | /* Remove CPU from timer broadcasting */ |
999 | tick_offline_cpu(cpu); | |
14e568e7 | 1000 | /* Park the stopper thread */ |
090e77c3 | 1001 | stop_machine_park(cpu); |
f3705136 | 1002 | return 0; |
1da177e4 LT |
1003 | } |
1004 | ||
98458172 | 1005 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 1006 | { |
e69aab13 | 1007 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 1008 | int err; |
1da177e4 | 1009 | |
2a58c527 | 1010 | /* Park the smpboot threads */ |
13070833 | 1011 | kthread_park(st->thread); |
1cf4f629 | 1012 | |
6acce3ef | 1013 | /* |
a8994181 TG |
1014 | * Prevent irq alloc/free while the dying cpu reorganizes the |
1015 | * interrupt affinities. | |
6acce3ef | 1016 | */ |
a8994181 | 1017 | irq_lock_sparse(); |
6acce3ef | 1018 | |
a8994181 TG |
1019 | /* |
1020 | * So now all preempt/rcu users must observe !cpu_active(). | |
1021 | */ | |
210e2133 | 1022 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 1023 | if (err) { |
3b9d6da6 | 1024 | /* CPU refused to die */ |
a8994181 | 1025 | irq_unlock_sparse(); |
3b9d6da6 | 1026 | /* Unpark the hotplug thread so we can rollback there */ |
13070833 | 1027 | kthread_unpark(st->thread); |
98458172 | 1028 | return err; |
8fa1d7d3 | 1029 | } |
04321587 | 1030 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 1031 | |
48c5ccae | 1032 | /* |
5b1ead68 BJ |
1033 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
1034 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 1035 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
1036 | * |
1037 | * Wait for the stop thread to go away. | |
48c5ccae | 1038 | */ |
5ebe7742 | 1039 | wait_for_ap_thread(st, false); |
e69aab13 | 1040 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 1041 | |
a8994181 TG |
1042 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
1043 | irq_unlock_sparse(); | |
1044 | ||
345527b1 | 1045 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
1046 | /* This actually kills the CPU. */ |
1047 | __cpu_die(cpu); | |
1048 | ||
a49b116d | 1049 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 1050 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
1051 | return 0; |
1052 | } | |
1da177e4 | 1053 | |
71f87b2f TG |
1054 | static void cpuhp_complete_idle_dead(void *arg) |
1055 | { | |
1056 | struct cpuhp_cpu_state *st = arg; | |
1057 | ||
5ebe7742 | 1058 | complete_ap_thread(st, false); |
71f87b2f TG |
1059 | } |
1060 | ||
e69aab13 TG |
1061 | void cpuhp_report_idle_dead(void) |
1062 | { | |
1063 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
1064 | ||
1065 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 1066 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
1067 | st->state = CPUHP_AP_IDLE_DEAD; |
1068 | /* | |
1069 | * We cannot call complete after rcu_report_dead() so we delegate it | |
1070 | * to an online cpu. | |
1071 | */ | |
1072 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
1073 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
1074 | } |
1075 | ||
4dddfb5f PZ |
1076 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
1077 | enum cpuhp_state target) | |
1078 | { | |
1079 | enum cpuhp_state prev_state = st->state; | |
1080 | int ret = 0; | |
1081 | ||
453e4108 VD |
1082 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
1083 | if (ret) { | |
1084 | ||
1085 | cpuhp_reset_state(st, prev_state); | |
1086 | ||
1087 | if (st->state < prev_state) | |
1088 | WARN_ON(cpuhp_invoke_callback_range(true, cpu, st, | |
1089 | prev_state)); | |
4dddfb5f | 1090 | } |
453e4108 | 1091 | |
4dddfb5f PZ |
1092 | return ret; |
1093 | } | |
cff7d378 | 1094 | |
98458172 | 1095 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
1096 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
1097 | enum cpuhp_state target) | |
98458172 | 1098 | { |
cff7d378 TG |
1099 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
1100 | int prev_state, ret = 0; | |
98458172 TG |
1101 | |
1102 | if (num_online_cpus() == 1) | |
1103 | return -EBUSY; | |
1104 | ||
757c989b | 1105 | if (!cpu_present(cpu)) |
98458172 TG |
1106 | return -EINVAL; |
1107 | ||
8f553c49 | 1108 | cpus_write_lock(); |
98458172 TG |
1109 | |
1110 | cpuhp_tasks_frozen = tasks_frozen; | |
1111 | ||
4dddfb5f | 1112 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
1113 | /* |
1114 | * If the current CPU state is in the range of the AP hotplug thread, | |
1115 | * then we need to kick the thread. | |
1116 | */ | |
8df3e07e | 1117 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 1118 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
1119 | ret = cpuhp_kick_ap_work(cpu); |
1120 | /* | |
1121 | * The AP side has done the error rollback already. Just | |
1122 | * return the error code.. | |
1123 | */ | |
1124 | if (ret) | |
1125 | goto out; | |
1126 | ||
1127 | /* | |
1128 | * We might have stopped still in the range of the AP hotplug | |
1129 | * thread. Nothing to do anymore. | |
1130 | */ | |
8df3e07e | 1131 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1132 | goto out; |
4dddfb5f PZ |
1133 | |
1134 | st->target = target; | |
1cf4f629 TG |
1135 | } |
1136 | /* | |
8df3e07e | 1137 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1138 | * to do the further cleanups. |
1139 | */ | |
a724632c | 1140 | ret = cpuhp_down_callbacks(cpu, st, target); |
62f25069 VD |
1141 | if (ret && st->state < prev_state) { |
1142 | if (st->state == CPUHP_TEARDOWN_CPU) { | |
1143 | cpuhp_reset_state(st, prev_state); | |
1144 | __cpuhp_kick_ap(st); | |
1145 | } else { | |
1146 | WARN(1, "DEAD callback error for CPU%d", cpu); | |
1147 | } | |
3b9d6da6 | 1148 | } |
98458172 | 1149 | |
1cf4f629 | 1150 | out: |
8f553c49 | 1151 | cpus_write_unlock(); |
941154bd TG |
1152 | /* |
1153 | * Do post unplug cleanup. This is still protected against | |
1154 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1155 | */ | |
1156 | lockup_detector_cleanup(); | |
a74cfffb | 1157 | arch_smt_update(); |
b22afcdf | 1158 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
cff7d378 | 1159 | return ret; |
e3920fb4 RW |
1160 | } |
1161 | ||
cc1fe215 TG |
1162 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1163 | { | |
1164 | if (cpu_hotplug_disabled) | |
1165 | return -EBUSY; | |
1166 | return _cpu_down(cpu, 0, target); | |
1167 | } | |
1168 | ||
33c3736e | 1169 | static int cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1170 | { |
9ea09af3 | 1171 | int err; |
e3920fb4 | 1172 | |
d221938c | 1173 | cpu_maps_update_begin(); |
cc1fe215 | 1174 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1175 | cpu_maps_update_done(); |
1da177e4 LT |
1176 | return err; |
1177 | } | |
4dddfb5f | 1178 | |
33c3736e QY |
1179 | /** |
1180 | * cpu_device_down - Bring down a cpu device | |
1181 | * @dev: Pointer to the cpu device to offline | |
1182 | * | |
1183 | * This function is meant to be used by device core cpu subsystem only. | |
1184 | * | |
1185 | * Other subsystems should use remove_cpu() instead. | |
1186 | */ | |
1187 | int cpu_device_down(struct device *dev) | |
af1f4045 | 1188 | { |
33c3736e | 1189 | return cpu_down(dev->id, CPUHP_OFFLINE); |
af1f4045 | 1190 | } |
4dddfb5f | 1191 | |
93ef1429 QY |
1192 | int remove_cpu(unsigned int cpu) |
1193 | { | |
1194 | int ret; | |
1195 | ||
1196 | lock_device_hotplug(); | |
1197 | ret = device_offline(get_cpu_device(cpu)); | |
1198 | unlock_device_hotplug(); | |
1199 | ||
1200 | return ret; | |
1201 | } | |
1202 | EXPORT_SYMBOL_GPL(remove_cpu); | |
1203 | ||
0441a559 QY |
1204 | void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) |
1205 | { | |
1206 | unsigned int cpu; | |
1207 | int error; | |
1208 | ||
1209 | cpu_maps_update_begin(); | |
1210 | ||
1211 | /* | |
1212 | * Make certain the cpu I'm about to reboot on is online. | |
1213 | * | |
1214 | * This is inline to what migrate_to_reboot_cpu() already do. | |
1215 | */ | |
1216 | if (!cpu_online(primary_cpu)) | |
1217 | primary_cpu = cpumask_first(cpu_online_mask); | |
1218 | ||
1219 | for_each_online_cpu(cpu) { | |
1220 | if (cpu == primary_cpu) | |
1221 | continue; | |
1222 | ||
1223 | error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1224 | if (error) { | |
1225 | pr_err("Failed to offline CPU%d - error=%d", | |
1226 | cpu, error); | |
1227 | break; | |
1228 | } | |
1229 | } | |
1230 | ||
1231 | /* | |
1232 | * Ensure all but the reboot CPU are offline. | |
1233 | */ | |
1234 | BUG_ON(num_online_cpus() > 1); | |
1235 | ||
1236 | /* | |
1237 | * Make sure the CPUs won't be enabled by someone else after this | |
1238 | * point. Kexec will reboot to a new kernel shortly resetting | |
1239 | * everything along the way. | |
1240 | */ | |
1241 | cpu_hotplug_disabled++; | |
1242 | ||
1243 | cpu_maps_update_done(); | |
af1f4045 | 1244 | } |
4dddfb5f PZ |
1245 | |
1246 | #else | |
1247 | #define takedown_cpu NULL | |
1da177e4 LT |
1248 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1249 | ||
4baa0afc | 1250 | /** |
ee1e714b | 1251 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1252 | * @cpu: cpu that just started |
1253 | * | |
4baa0afc TG |
1254 | * It must be called by the arch code on the new cpu, before the new cpu |
1255 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1256 | */ | |
1257 | void notify_cpu_starting(unsigned int cpu) | |
1258 | { | |
1259 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1260 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1261 | int ret; |
4baa0afc | 1262 | |
0c6d4576 | 1263 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1264 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
453e4108 VD |
1265 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
1266 | ||
1267 | /* | |
1268 | * STARTING must not fail! | |
1269 | */ | |
1270 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1271 | } |
1272 | ||
949338e3 | 1273 | /* |
9cd4f1a4 | 1274 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1275 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1276 | * online bringup to the hotplug thread. | |
949338e3 | 1277 | */ |
8df3e07e | 1278 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1279 | { |
8df3e07e | 1280 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1281 | |
1282 | /* Happens for the boot cpu */ | |
1283 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1284 | return; | |
1285 | ||
45178ac0 PZ |
1286 | /* |
1287 | * Unpart the stopper thread before we start the idle loop (and start | |
1288 | * scheduling); this ensures the stopper task is always available. | |
1289 | */ | |
1290 | stop_machine_unpark(smp_processor_id()); | |
1291 | ||
8df3e07e | 1292 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1293 | complete_ap_thread(st, true); |
949338e3 TG |
1294 | } |
1295 | ||
e3920fb4 | 1296 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1297 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1298 | { |
cff7d378 | 1299 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1300 | struct task_struct *idle; |
2e1a3483 | 1301 | int ret = 0; |
1da177e4 | 1302 | |
8f553c49 | 1303 | cpus_write_lock(); |
38498a67 | 1304 | |
757c989b | 1305 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1306 | ret = -EINVAL; |
1307 | goto out; | |
1308 | } | |
1309 | ||
757c989b | 1310 | /* |
33c3736e QY |
1311 | * The caller of cpu_up() might have raced with another |
1312 | * caller. Nothing to do. | |
757c989b TG |
1313 | */ |
1314 | if (st->state >= target) | |
38498a67 | 1315 | goto out; |
757c989b TG |
1316 | |
1317 | if (st->state == CPUHP_OFFLINE) { | |
1318 | /* Let it fail before we try to bring the cpu up */ | |
1319 | idle = idle_thread_get(cpu); | |
1320 | if (IS_ERR(idle)) { | |
1321 | ret = PTR_ERR(idle); | |
1322 | goto out; | |
1323 | } | |
3bb5d2ee | 1324 | } |
38498a67 | 1325 | |
ba997462 TG |
1326 | cpuhp_tasks_frozen = tasks_frozen; |
1327 | ||
4dddfb5f | 1328 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1329 | /* |
1330 | * If the current CPU state is in the range of the AP hotplug thread, | |
1331 | * then we need to kick the thread once more. | |
1332 | */ | |
8df3e07e | 1333 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1334 | ret = cpuhp_kick_ap_work(cpu); |
1335 | /* | |
1336 | * The AP side has done the error rollback already. Just | |
1337 | * return the error code.. | |
1338 | */ | |
1339 | if (ret) | |
1340 | goto out; | |
1341 | } | |
1342 | ||
1343 | /* | |
1344 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1345 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1346 | * responsible for bringing it up to the target state. |
1347 | */ | |
8df3e07e | 1348 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1349 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1350 | out: |
8f553c49 | 1351 | cpus_write_unlock(); |
a74cfffb | 1352 | arch_smt_update(); |
b22afcdf | 1353 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
e3920fb4 RW |
1354 | return ret; |
1355 | } | |
1356 | ||
33c3736e | 1357 | static int cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1358 | { |
1359 | int err = 0; | |
cf23422b | 1360 | |
e0b582ec | 1361 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1362 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1363 | cpu); | |
87d5e023 | 1364 | #if defined(CONFIG_IA64) |
84117da5 | 1365 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1366 | #endif |
1367 | return -EINVAL; | |
1368 | } | |
e3920fb4 | 1369 | |
01b0f197 TK |
1370 | err = try_online_node(cpu_to_node(cpu)); |
1371 | if (err) | |
1372 | return err; | |
cf23422b | 1373 | |
d221938c | 1374 | cpu_maps_update_begin(); |
e761b772 MK |
1375 | |
1376 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1377 | err = -EBUSY; |
e761b772 MK |
1378 | goto out; |
1379 | } | |
05736e4a TG |
1380 | if (!cpu_smt_allowed(cpu)) { |
1381 | err = -EPERM; | |
1382 | goto out; | |
1383 | } | |
e761b772 | 1384 | |
af1f4045 | 1385 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1386 | out: |
d221938c | 1387 | cpu_maps_update_done(); |
e3920fb4 RW |
1388 | return err; |
1389 | } | |
af1f4045 | 1390 | |
33c3736e QY |
1391 | /** |
1392 | * cpu_device_up - Bring up a cpu device | |
1393 | * @dev: Pointer to the cpu device to online | |
1394 | * | |
1395 | * This function is meant to be used by device core cpu subsystem only. | |
1396 | * | |
1397 | * Other subsystems should use add_cpu() instead. | |
1398 | */ | |
1399 | int cpu_device_up(struct device *dev) | |
af1f4045 | 1400 | { |
33c3736e | 1401 | return cpu_up(dev->id, CPUHP_ONLINE); |
af1f4045 | 1402 | } |
e3920fb4 | 1403 | |
93ef1429 QY |
1404 | int add_cpu(unsigned int cpu) |
1405 | { | |
1406 | int ret; | |
1407 | ||
1408 | lock_device_hotplug(); | |
1409 | ret = device_online(get_cpu_device(cpu)); | |
1410 | unlock_device_hotplug(); | |
1411 | ||
1412 | return ret; | |
1413 | } | |
1414 | EXPORT_SYMBOL_GPL(add_cpu); | |
1415 | ||
d720f986 QY |
1416 | /** |
1417 | * bringup_hibernate_cpu - Bring up the CPU that we hibernated on | |
1418 | * @sleep_cpu: The cpu we hibernated on and should be brought up. | |
1419 | * | |
1420 | * On some architectures like arm64, we can hibernate on any CPU, but on | |
1421 | * wake up the CPU we hibernated on might be offline as a side effect of | |
1422 | * using maxcpus= for example. | |
1423 | */ | |
1424 | int bringup_hibernate_cpu(unsigned int sleep_cpu) | |
af1f4045 | 1425 | { |
d720f986 QY |
1426 | int ret; |
1427 | ||
1428 | if (!cpu_online(sleep_cpu)) { | |
1429 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
33c3736e | 1430 | ret = cpu_up(sleep_cpu, CPUHP_ONLINE); |
d720f986 QY |
1431 | if (ret) { |
1432 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
1433 | return ret; | |
1434 | } | |
1435 | } | |
1436 | return 0; | |
1437 | } | |
1438 | ||
b99a2659 QY |
1439 | void bringup_nonboot_cpus(unsigned int setup_max_cpus) |
1440 | { | |
1441 | unsigned int cpu; | |
1442 | ||
1443 | for_each_present_cpu(cpu) { | |
1444 | if (num_online_cpus() >= setup_max_cpus) | |
1445 | break; | |
1446 | if (!cpu_online(cpu)) | |
33c3736e | 1447 | cpu_up(cpu, CPUHP_ONLINE); |
b99a2659 | 1448 | } |
af1f4045 | 1449 | } |
e3920fb4 | 1450 | |
f3de4be9 | 1451 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1452 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1453 | |
fb7fb84a | 1454 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1455 | { |
d391e552 | 1456 | int cpu, error = 0; |
e3920fb4 | 1457 | |
d221938c | 1458 | cpu_maps_update_begin(); |
9ca12ac0 | 1459 | if (primary == -1) { |
d391e552 | 1460 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1461 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1462 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1463 | } else { | |
1464 | if (!cpu_online(primary)) | |
1465 | primary = cpumask_first(cpu_online_mask); | |
1466 | } | |
1467 | ||
9ee349ad XF |
1468 | /* |
1469 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1470 | * with the userspace trying to use the CPU hotplug at the same time |
1471 | */ | |
e0b582ec | 1472 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1473 | |
84117da5 | 1474 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1475 | for_each_online_cpu(cpu) { |
d391e552 | 1476 | if (cpu == primary) |
e3920fb4 | 1477 | continue; |
a66d955e | 1478 | |
fb7fb84a | 1479 | if (pm_wakeup_pending()) { |
a66d955e PK |
1480 | pr_info("Wakeup pending. Abort CPU freeze\n"); |
1481 | error = -EBUSY; | |
1482 | break; | |
1483 | } | |
1484 | ||
bb3632c6 | 1485 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1486 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1487 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1488 | if (!error) |
e0b582ec | 1489 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1490 | else { |
84117da5 | 1491 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1492 | break; |
1493 | } | |
1494 | } | |
86886e55 | 1495 | |
89af7ba5 | 1496 | if (!error) |
e3920fb4 | 1497 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1498 | else |
84117da5 | 1499 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1500 | |
1501 | /* | |
1502 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
56555855 QY |
1503 | * this even in case of failure as all freeze_secondary_cpus() users are |
1504 | * supposed to do thaw_secondary_cpus() on the failure path. | |
89af7ba5 VK |
1505 | */ |
1506 | cpu_hotplug_disabled++; | |
1507 | ||
d221938c | 1508 | cpu_maps_update_done(); |
e3920fb4 RW |
1509 | return error; |
1510 | } | |
1511 | ||
56555855 | 1512 | void __weak arch_thaw_secondary_cpus_begin(void) |
d0af9eed SS |
1513 | { |
1514 | } | |
1515 | ||
56555855 | 1516 | void __weak arch_thaw_secondary_cpus_end(void) |
d0af9eed SS |
1517 | { |
1518 | } | |
1519 | ||
56555855 | 1520 | void thaw_secondary_cpus(void) |
e3920fb4 RW |
1521 | { |
1522 | int cpu, error; | |
1523 | ||
1524 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1525 | cpu_maps_update_begin(); |
01b41159 | 1526 | __cpu_hotplug_enable(); |
e0b582ec | 1527 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1528 | goto out; |
e3920fb4 | 1529 | |
84117da5 | 1530 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed | 1531 | |
56555855 | 1532 | arch_thaw_secondary_cpus_begin(); |
d0af9eed | 1533 | |
e0b582ec | 1534 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1535 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1536 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1537 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1538 | if (!error) { |
84117da5 | 1539 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1540 | continue; |
1541 | } | |
84117da5 | 1542 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1543 | } |
d0af9eed | 1544 | |
56555855 | 1545 | arch_thaw_secondary_cpus_end(); |
d0af9eed | 1546 | |
e0b582ec | 1547 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1548 | out: |
d221938c | 1549 | cpu_maps_update_done(); |
1da177e4 | 1550 | } |
e0b582ec | 1551 | |
d7268a31 | 1552 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1553 | { |
1554 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1555 | return -ENOMEM; | |
1556 | return 0; | |
1557 | } | |
1558 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1559 | |
79cfbdfa SB |
1560 | /* |
1561 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1562 | * ensure that the state of the system with respect to the tasks being frozen | |
1563 | * or not, as reported by the notification, remains unchanged *throughout the | |
1564 | * duration* of the execution of the callbacks. | |
1565 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1566 | * | |
1567 | * This synchronization is implemented by mutually excluding regular CPU | |
1568 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1569 | * Hibernate notifications. | |
1570 | */ | |
1571 | static int | |
1572 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1573 | unsigned long action, void *ptr) | |
1574 | { | |
1575 | switch (action) { | |
1576 | ||
1577 | case PM_SUSPEND_PREPARE: | |
1578 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1579 | cpu_hotplug_disable(); |
79cfbdfa SB |
1580 | break; |
1581 | ||
1582 | case PM_POST_SUSPEND: | |
1583 | case PM_POST_HIBERNATION: | |
16e53dbf | 1584 | cpu_hotplug_enable(); |
79cfbdfa SB |
1585 | break; |
1586 | ||
1587 | default: | |
1588 | return NOTIFY_DONE; | |
1589 | } | |
1590 | ||
1591 | return NOTIFY_OK; | |
1592 | } | |
1593 | ||
1594 | ||
d7268a31 | 1595 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1596 | { |
6e32d479 FY |
1597 | /* |
1598 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1599 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1600 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1601 | */ | |
79cfbdfa SB |
1602 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1603 | return 0; | |
1604 | } | |
1605 | core_initcall(cpu_hotplug_pm_sync_init); | |
1606 | ||
f3de4be9 | 1607 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1608 | |
8ce371f9 PZ |
1609 | int __boot_cpu_id; |
1610 | ||
68f4f1ec | 1611 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1612 | |
cff7d378 | 1613 | /* Boot processor state steps */ |
17a2f1ce | 1614 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1615 | [CPUHP_OFFLINE] = { |
1616 | .name = "offline", | |
3c1627e9 TG |
1617 | .startup.single = NULL, |
1618 | .teardown.single = NULL, | |
cff7d378 TG |
1619 | }, |
1620 | #ifdef CONFIG_SMP | |
1621 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1622 | .name = "threads:prepare", |
3c1627e9 TG |
1623 | .startup.single = smpboot_create_threads, |
1624 | .teardown.single = NULL, | |
757c989b | 1625 | .cant_stop = true, |
cff7d378 | 1626 | }, |
00e16c3d | 1627 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1628 | .name = "perf:prepare", |
1629 | .startup.single = perf_event_init_cpu, | |
1630 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1631 | }, |
7ee681b2 | 1632 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1633 | .name = "workqueue:prepare", |
1634 | .startup.single = workqueue_prepare_cpu, | |
1635 | .teardown.single = NULL, | |
7ee681b2 | 1636 | }, |
27590dc1 | 1637 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1638 | .name = "hrtimers:prepare", |
1639 | .startup.single = hrtimers_prepare_cpu, | |
1640 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1641 | }, |
31487f83 | 1642 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1643 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1644 | .startup.single = smpcfd_prepare_cpu, |
1645 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1646 | }, |
e6d4989a RW |
1647 | [CPUHP_RELAY_PREPARE] = { |
1648 | .name = "relay:prepare", | |
1649 | .startup.single = relay_prepare_cpu, | |
1650 | .teardown.single = NULL, | |
1651 | }, | |
6731d4f1 SAS |
1652 | [CPUHP_SLAB_PREPARE] = { |
1653 | .name = "slab:prepare", | |
1654 | .startup.single = slab_prepare_cpu, | |
1655 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1656 | }, |
4df83742 | 1657 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1658 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1659 | .startup.single = rcutree_prepare_cpu, |
1660 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1661 | }, |
4fae16df RC |
1662 | /* |
1663 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1664 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1665 | * otherwise a RCU stall occurs. | |
1666 | */ | |
26456f87 | 1667 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1668 | .name = "timers:prepare", |
26456f87 | 1669 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1670 | .teardown.single = timers_dead_cpu, |
4fae16df | 1671 | }, |
d10ef6f9 | 1672 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1673 | [CPUHP_BRINGUP_CPU] = { |
1674 | .name = "cpu:bringup", | |
3c1627e9 | 1675 | .startup.single = bringup_cpu, |
bf2c59fc | 1676 | .teardown.single = finish_cpu, |
757c989b | 1677 | .cant_stop = true, |
4baa0afc | 1678 | }, |
d10ef6f9 TG |
1679 | /* Final state before CPU kills itself */ |
1680 | [CPUHP_AP_IDLE_DEAD] = { | |
1681 | .name = "idle:dead", | |
1682 | }, | |
1683 | /* | |
1684 | * Last state before CPU enters the idle loop to die. Transient state | |
1685 | * for synchronization. | |
1686 | */ | |
1687 | [CPUHP_AP_OFFLINE] = { | |
1688 | .name = "ap:offline", | |
1689 | .cant_stop = true, | |
1690 | }, | |
9cf7243d TG |
1691 | /* First state is scheduler control. Interrupts are disabled */ |
1692 | [CPUHP_AP_SCHED_STARTING] = { | |
1693 | .name = "sched:starting", | |
3c1627e9 TG |
1694 | .startup.single = sched_cpu_starting, |
1695 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1696 | }, |
4df83742 | 1697 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1698 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1699 | .startup.single = NULL, |
1700 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1701 | }, |
46febd37 LJ |
1702 | [CPUHP_AP_SMPCFD_DYING] = { |
1703 | .name = "smpcfd:dying", | |
1704 | .startup.single = NULL, | |
1705 | .teardown.single = smpcfd_dying_cpu, | |
1706 | }, | |
d10ef6f9 TG |
1707 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1708 | * state for synchronsization */ | |
1709 | [CPUHP_AP_ONLINE] = { | |
1710 | .name = "ap:online", | |
1711 | }, | |
17a2f1ce | 1712 | /* |
1cf12e08 | 1713 | * Handled on control processor until the plugged processor manages |
17a2f1ce LJ |
1714 | * this itself. |
1715 | */ | |
1716 | [CPUHP_TEARDOWN_CPU] = { | |
1717 | .name = "cpu:teardown", | |
1718 | .startup.single = NULL, | |
1719 | .teardown.single = takedown_cpu, | |
1720 | .cant_stop = true, | |
1721 | }, | |
1cf12e08 TG |
1722 | |
1723 | [CPUHP_AP_SCHED_WAIT_EMPTY] = { | |
1724 | .name = "sched:waitempty", | |
1725 | .startup.single = NULL, | |
1726 | .teardown.single = sched_cpu_wait_empty, | |
1727 | }, | |
1728 | ||
d10ef6f9 | 1729 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1730 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1731 | .name = "smpboot/threads:online", |
3c1627e9 | 1732 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1733 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1734 | }, |
c5cb83bb TG |
1735 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1736 | .name = "irq/affinity:online", | |
1737 | .startup.single = irq_affinity_online_cpu, | |
1738 | .teardown.single = NULL, | |
1739 | }, | |
00e16c3d | 1740 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1741 | .name = "perf:online", |
1742 | .startup.single = perf_event_init_cpu, | |
1743 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1744 | }, |
9cf57731 PZ |
1745 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1746 | .name = "lockup_detector:online", | |
1747 | .startup.single = lockup_detector_online_cpu, | |
1748 | .teardown.single = lockup_detector_offline_cpu, | |
1749 | }, | |
7ee681b2 | 1750 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1751 | .name = "workqueue:online", |
1752 | .startup.single = workqueue_online_cpu, | |
1753 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1754 | }, |
4df83742 | 1755 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1756 | .name = "RCU/tree:online", |
3c1627e9 TG |
1757 | .startup.single = rcutree_online_cpu, |
1758 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1759 | }, |
4baa0afc | 1760 | #endif |
d10ef6f9 TG |
1761 | /* |
1762 | * The dynamically registered state space is here | |
1763 | */ | |
1764 | ||
aaddd7d1 TG |
1765 | #ifdef CONFIG_SMP |
1766 | /* Last state is scheduler control setting the cpu active */ | |
1767 | [CPUHP_AP_ACTIVE] = { | |
1768 | .name = "sched:active", | |
3c1627e9 TG |
1769 | .startup.single = sched_cpu_activate, |
1770 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1771 | }, |
1772 | #endif | |
1773 | ||
d10ef6f9 | 1774 | /* CPU is fully up and running. */ |
4baa0afc TG |
1775 | [CPUHP_ONLINE] = { |
1776 | .name = "online", | |
3c1627e9 TG |
1777 | .startup.single = NULL, |
1778 | .teardown.single = NULL, | |
4baa0afc TG |
1779 | }, |
1780 | }; | |
1781 | ||
5b7aa87e TG |
1782 | /* Sanity check for callbacks */ |
1783 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1784 | { | |
1785 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1786 | return -EINVAL; | |
1787 | return 0; | |
1788 | } | |
1789 | ||
dc280d93 TG |
1790 | /* |
1791 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1792 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1793 | * by having no name assigned. | |
1794 | */ | |
1795 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1796 | { | |
4205e478 TG |
1797 | enum cpuhp_state i, end; |
1798 | struct cpuhp_step *step; | |
dc280d93 | 1799 | |
4205e478 TG |
1800 | switch (state) { |
1801 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1802 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1803 | end = CPUHP_AP_ONLINE_DYN_END; |
1804 | break; | |
1805 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1806 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1807 | end = CPUHP_BP_PREPARE_DYN_END; |
1808 | break; | |
1809 | default: | |
1810 | return -EINVAL; | |
1811 | } | |
1812 | ||
1813 | for (i = state; i <= end; i++, step++) { | |
1814 | if (!step->name) | |
dc280d93 TG |
1815 | return i; |
1816 | } | |
1817 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1818 | return -ENOSPC; | |
1819 | } | |
1820 | ||
1821 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1822 | int (*startup)(unsigned int cpu), | |
1823 | int (*teardown)(unsigned int cpu), | |
1824 | bool multi_instance) | |
5b7aa87e TG |
1825 | { |
1826 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1827 | struct cpuhp_step *sp; | |
dc280d93 | 1828 | int ret = 0; |
5b7aa87e | 1829 | |
0c96b273 EB |
1830 | /* |
1831 | * If name is NULL, then the state gets removed. | |
1832 | * | |
1833 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1834 | * the first allocation from these dynamic ranges, so the removal | |
1835 | * would trigger a new allocation and clear the wrong (already | |
1836 | * empty) state, leaving the callbacks of the to be cleared state | |
1837 | * dangling, which causes wreckage on the next hotplug operation. | |
1838 | */ | |
1839 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1840 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1841 | ret = cpuhp_reserve_state(state); |
1842 | if (ret < 0) | |
dc434e05 | 1843 | return ret; |
dc280d93 TG |
1844 | state = ret; |
1845 | } | |
5b7aa87e | 1846 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1847 | if (name && sp->name) |
1848 | return -EBUSY; | |
1849 | ||
3c1627e9 TG |
1850 | sp->startup.single = startup; |
1851 | sp->teardown.single = teardown; | |
5b7aa87e | 1852 | sp->name = name; |
cf392d10 TG |
1853 | sp->multi_instance = multi_instance; |
1854 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1855 | return ret; |
5b7aa87e TG |
1856 | } |
1857 | ||
1858 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1859 | { | |
3c1627e9 | 1860 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1861 | } |
1862 | ||
5b7aa87e TG |
1863 | /* |
1864 | * Call the startup/teardown function for a step either on the AP or | |
1865 | * on the current CPU. | |
1866 | */ | |
cf392d10 TG |
1867 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1868 | struct hlist_node *node) | |
5b7aa87e | 1869 | { |
a724632c | 1870 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1871 | int ret; |
1872 | ||
4dddfb5f PZ |
1873 | /* |
1874 | * If there's nothing to do, we done. | |
1875 | * Relies on the union for multi_instance. | |
1876 | */ | |
453e4108 | 1877 | if (cpuhp_step_empty(bringup, sp)) |
5b7aa87e | 1878 | return 0; |
5b7aa87e TG |
1879 | /* |
1880 | * The non AP bound callbacks can fail on bringup. On teardown | |
1881 | * e.g. module removal we crash for now. | |
1882 | */ | |
1cf4f629 TG |
1883 | #ifdef CONFIG_SMP |
1884 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1885 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1886 | else |
96abb968 | 1887 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1888 | #else |
96abb968 | 1889 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1890 | #endif |
5b7aa87e TG |
1891 | BUG_ON(ret && !bringup); |
1892 | return ret; | |
1893 | } | |
1894 | ||
1895 | /* | |
1896 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1897 | * | |
1898 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1899 | */ | |
1900 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1901 | struct hlist_node *node) |
5b7aa87e TG |
1902 | { |
1903 | int cpu; | |
1904 | ||
5b7aa87e TG |
1905 | /* Roll back the already executed steps on the other cpus */ |
1906 | for_each_present_cpu(cpu) { | |
1907 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1908 | int cpustate = st->state; | |
1909 | ||
1910 | if (cpu >= failedcpu) | |
1911 | break; | |
1912 | ||
1913 | /* Did we invoke the startup call on that cpu ? */ | |
1914 | if (cpustate >= state) | |
cf392d10 | 1915 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1916 | } |
1917 | } | |
1918 | ||
9805c673 TG |
1919 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1920 | struct hlist_node *node, | |
1921 | bool invoke) | |
cf392d10 TG |
1922 | { |
1923 | struct cpuhp_step *sp; | |
1924 | int cpu; | |
1925 | int ret; | |
1926 | ||
9805c673 TG |
1927 | lockdep_assert_cpus_held(); |
1928 | ||
cf392d10 TG |
1929 | sp = cpuhp_get_step(state); |
1930 | if (sp->multi_instance == false) | |
1931 | return -EINVAL; | |
1932 | ||
dc434e05 | 1933 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1934 | |
3c1627e9 | 1935 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1936 | goto add_node; |
1937 | ||
1938 | /* | |
1939 | * Try to call the startup callback for each present cpu | |
1940 | * depending on the hotplug state of the cpu. | |
1941 | */ | |
1942 | for_each_present_cpu(cpu) { | |
1943 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1944 | int cpustate = st->state; | |
1945 | ||
1946 | if (cpustate < state) | |
1947 | continue; | |
1948 | ||
1949 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1950 | if (ret) { | |
3c1627e9 | 1951 | if (sp->teardown.multi) |
cf392d10 | 1952 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1953 | goto unlock; |
cf392d10 TG |
1954 | } |
1955 | } | |
1956 | add_node: | |
1957 | ret = 0; | |
cf392d10 | 1958 | hlist_add_head(node, &sp->list); |
dc434e05 | 1959 | unlock: |
cf392d10 | 1960 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1961 | return ret; |
1962 | } | |
1963 | ||
1964 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1965 | bool invoke) | |
1966 | { | |
1967 | int ret; | |
1968 | ||
1969 | cpus_read_lock(); | |
1970 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1971 | cpus_read_unlock(); |
cf392d10 TG |
1972 | return ret; |
1973 | } | |
1974 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1975 | ||
5b7aa87e | 1976 | /** |
71def423 | 1977 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1978 | * @state: The state to setup |
1979 | * @invoke: If true, the startup function is invoked for cpus where | |
1980 | * cpu state >= @state | |
1981 | * @startup: startup callback function | |
1982 | * @teardown: teardown callback function | |
1983 | * @multi_instance: State is set up for multiple instances which get | |
1984 | * added afterwards. | |
5b7aa87e | 1985 | * |
71def423 | 1986 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1987 | * Returns: |
1988 | * On success: | |
1989 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1990 | * 0 for all other states | |
1991 | * On failure: proper (negative) error code | |
5b7aa87e | 1992 | */ |
71def423 SAS |
1993 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1994 | const char *name, bool invoke, | |
1995 | int (*startup)(unsigned int cpu), | |
1996 | int (*teardown)(unsigned int cpu), | |
1997 | bool multi_instance) | |
5b7aa87e TG |
1998 | { |
1999 | int cpu, ret = 0; | |
b9d9d691 | 2000 | bool dynstate; |
5b7aa87e | 2001 | |
71def423 SAS |
2002 | lockdep_assert_cpus_held(); |
2003 | ||
5b7aa87e TG |
2004 | if (cpuhp_cb_check(state) || !name) |
2005 | return -EINVAL; | |
2006 | ||
dc434e05 | 2007 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 2008 | |
dc280d93 TG |
2009 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
2010 | multi_instance); | |
5b7aa87e | 2011 | |
b9d9d691 TG |
2012 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
2013 | if (ret > 0 && dynstate) { | |
2014 | state = ret; | |
2015 | ret = 0; | |
2016 | } | |
2017 | ||
dc280d93 | 2018 | if (ret || !invoke || !startup) |
5b7aa87e TG |
2019 | goto out; |
2020 | ||
2021 | /* | |
2022 | * Try to call the startup callback for each present cpu | |
2023 | * depending on the hotplug state of the cpu. | |
2024 | */ | |
2025 | for_each_present_cpu(cpu) { | |
2026 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2027 | int cpustate = st->state; | |
2028 | ||
2029 | if (cpustate < state) | |
2030 | continue; | |
2031 | ||
cf392d10 | 2032 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 2033 | if (ret) { |
a724632c | 2034 | if (teardown) |
cf392d10 TG |
2035 | cpuhp_rollback_install(cpu, state, NULL); |
2036 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
2037 | goto out; |
2038 | } | |
2039 | } | |
2040 | out: | |
dc434e05 | 2041 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
2042 | /* |
2043 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
2044 | * dynamically allocated state in case of success. | |
2045 | */ | |
b9d9d691 | 2046 | if (!ret && dynstate) |
5b7aa87e TG |
2047 | return state; |
2048 | return ret; | |
2049 | } | |
71def423 SAS |
2050 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
2051 | ||
2052 | int __cpuhp_setup_state(enum cpuhp_state state, | |
2053 | const char *name, bool invoke, | |
2054 | int (*startup)(unsigned int cpu), | |
2055 | int (*teardown)(unsigned int cpu), | |
2056 | bool multi_instance) | |
2057 | { | |
2058 | int ret; | |
2059 | ||
2060 | cpus_read_lock(); | |
2061 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
2062 | teardown, multi_instance); | |
2063 | cpus_read_unlock(); | |
2064 | return ret; | |
2065 | } | |
5b7aa87e TG |
2066 | EXPORT_SYMBOL(__cpuhp_setup_state); |
2067 | ||
cf392d10 TG |
2068 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
2069 | struct hlist_node *node, bool invoke) | |
2070 | { | |
2071 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
2072 | int cpu; | |
2073 | ||
2074 | BUG_ON(cpuhp_cb_check(state)); | |
2075 | ||
2076 | if (!sp->multi_instance) | |
2077 | return -EINVAL; | |
2078 | ||
8f553c49 | 2079 | cpus_read_lock(); |
dc434e05 SAS |
2080 | mutex_lock(&cpuhp_state_mutex); |
2081 | ||
cf392d10 TG |
2082 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
2083 | goto remove; | |
2084 | /* | |
2085 | * Call the teardown callback for each present cpu depending | |
2086 | * on the hotplug state of the cpu. This function is not | |
2087 | * allowed to fail currently! | |
2088 | */ | |
2089 | for_each_present_cpu(cpu) { | |
2090 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2091 | int cpustate = st->state; | |
2092 | ||
2093 | if (cpustate >= state) | |
2094 | cpuhp_issue_call(cpu, state, false, node); | |
2095 | } | |
2096 | ||
2097 | remove: | |
cf392d10 TG |
2098 | hlist_del(node); |
2099 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 2100 | cpus_read_unlock(); |
cf392d10 TG |
2101 | |
2102 | return 0; | |
2103 | } | |
2104 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 2105 | |
5b7aa87e | 2106 | /** |
71def423 | 2107 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
2108 | * @state: The state to remove |
2109 | * @invoke: If true, the teardown function is invoked for cpus where | |
2110 | * cpu state >= @state | |
2111 | * | |
71def423 | 2112 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
2113 | * The teardown callback is currently not allowed to fail. Think |
2114 | * about module removal! | |
2115 | */ | |
71def423 | 2116 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 2117 | { |
cf392d10 | 2118 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
2119 | int cpu; |
2120 | ||
2121 | BUG_ON(cpuhp_cb_check(state)); | |
2122 | ||
71def423 | 2123 | lockdep_assert_cpus_held(); |
5b7aa87e | 2124 | |
dc434e05 | 2125 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
2126 | if (sp->multi_instance) { |
2127 | WARN(!hlist_empty(&sp->list), | |
2128 | "Error: Removing state %d which has instances left.\n", | |
2129 | state); | |
2130 | goto remove; | |
2131 | } | |
2132 | ||
a724632c | 2133 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
2134 | goto remove; |
2135 | ||
2136 | /* | |
2137 | * Call the teardown callback for each present cpu depending | |
2138 | * on the hotplug state of the cpu. This function is not | |
2139 | * allowed to fail currently! | |
2140 | */ | |
2141 | for_each_present_cpu(cpu) { | |
2142 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2143 | int cpustate = st->state; | |
2144 | ||
2145 | if (cpustate >= state) | |
cf392d10 | 2146 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
2147 | } |
2148 | remove: | |
cf392d10 | 2149 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 2150 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
2151 | } |
2152 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
2153 | ||
2154 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
2155 | { | |
2156 | cpus_read_lock(); | |
2157 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 2158 | cpus_read_unlock(); |
5b7aa87e TG |
2159 | } |
2160 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
2161 | ||
dc8d37ed AB |
2162 | #ifdef CONFIG_HOTPLUG_SMT |
2163 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2164 | { | |
2165 | struct device *dev = get_cpu_device(cpu); | |
2166 | ||
2167 | dev->offline = true; | |
2168 | /* Tell user space about the state change */ | |
2169 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2170 | } | |
2171 | ||
2172 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
2173 | { | |
2174 | struct device *dev = get_cpu_device(cpu); | |
2175 | ||
2176 | dev->offline = false; | |
2177 | /* Tell user space about the state change */ | |
2178 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2179 | } | |
2180 | ||
2181 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
2182 | { | |
2183 | int cpu, ret = 0; | |
2184 | ||
2185 | cpu_maps_update_begin(); | |
2186 | for_each_online_cpu(cpu) { | |
2187 | if (topology_is_primary_thread(cpu)) | |
2188 | continue; | |
2189 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2190 | if (ret) | |
2191 | break; | |
2192 | /* | |
2193 | * As this needs to hold the cpu maps lock it's impossible | |
2194 | * to call device_offline() because that ends up calling | |
2195 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2196 | * needs to be held as this might race against in kernel | |
2197 | * abusers of the hotplug machinery (thermal management). | |
2198 | * | |
2199 | * So nothing would update device:offline state. That would | |
2200 | * leave the sysfs entry stale and prevent onlining after | |
2201 | * smt control has been changed to 'off' again. This is | |
2202 | * called under the sysfs hotplug lock, so it is properly | |
2203 | * serialized against the regular offline usage. | |
2204 | */ | |
2205 | cpuhp_offline_cpu_device(cpu); | |
2206 | } | |
2207 | if (!ret) | |
2208 | cpu_smt_control = ctrlval; | |
2209 | cpu_maps_update_done(); | |
2210 | return ret; | |
2211 | } | |
2212 | ||
2213 | int cpuhp_smt_enable(void) | |
2214 | { | |
2215 | int cpu, ret = 0; | |
2216 | ||
2217 | cpu_maps_update_begin(); | |
2218 | cpu_smt_control = CPU_SMT_ENABLED; | |
2219 | for_each_present_cpu(cpu) { | |
2220 | /* Skip online CPUs and CPUs on offline nodes */ | |
2221 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2222 | continue; | |
2223 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2224 | if (ret) | |
2225 | break; | |
2226 | /* See comment in cpuhp_smt_disable() */ | |
2227 | cpuhp_online_cpu_device(cpu); | |
2228 | } | |
2229 | cpu_maps_update_done(); | |
2230 | return ret; | |
2231 | } | |
2232 | #endif | |
2233 | ||
98f8cdce TG |
2234 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
2235 | static ssize_t show_cpuhp_state(struct device *dev, | |
2236 | struct device_attribute *attr, char *buf) | |
2237 | { | |
2238 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2239 | ||
2240 | return sprintf(buf, "%d\n", st->state); | |
2241 | } | |
2242 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
2243 | ||
757c989b TG |
2244 | static ssize_t write_cpuhp_target(struct device *dev, |
2245 | struct device_attribute *attr, | |
2246 | const char *buf, size_t count) | |
2247 | { | |
2248 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2249 | struct cpuhp_step *sp; | |
2250 | int target, ret; | |
2251 | ||
2252 | ret = kstrtoint(buf, 10, &target); | |
2253 | if (ret) | |
2254 | return ret; | |
2255 | ||
2256 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2257 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2258 | return -EINVAL; | |
2259 | #else | |
2260 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2261 | return -EINVAL; | |
2262 | #endif | |
2263 | ||
2264 | ret = lock_device_hotplug_sysfs(); | |
2265 | if (ret) | |
2266 | return ret; | |
2267 | ||
2268 | mutex_lock(&cpuhp_state_mutex); | |
2269 | sp = cpuhp_get_step(target); | |
2270 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2271 | mutex_unlock(&cpuhp_state_mutex); | |
2272 | if (ret) | |
40da1b11 | 2273 | goto out; |
757c989b TG |
2274 | |
2275 | if (st->state < target) | |
33c3736e | 2276 | ret = cpu_up(dev->id, target); |
757c989b | 2277 | else |
33c3736e | 2278 | ret = cpu_down(dev->id, target); |
40da1b11 | 2279 | out: |
757c989b TG |
2280 | unlock_device_hotplug(); |
2281 | return ret ? ret : count; | |
2282 | } | |
2283 | ||
98f8cdce TG |
2284 | static ssize_t show_cpuhp_target(struct device *dev, |
2285 | struct device_attribute *attr, char *buf) | |
2286 | { | |
2287 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2288 | ||
2289 | return sprintf(buf, "%d\n", st->target); | |
2290 | } | |
757c989b | 2291 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 2292 | |
1db49484 PZ |
2293 | |
2294 | static ssize_t write_cpuhp_fail(struct device *dev, | |
2295 | struct device_attribute *attr, | |
2296 | const char *buf, size_t count) | |
2297 | { | |
2298 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2299 | struct cpuhp_step *sp; | |
2300 | int fail, ret; | |
2301 | ||
2302 | ret = kstrtoint(buf, 10, &fail); | |
2303 | if (ret) | |
2304 | return ret; | |
2305 | ||
3ae70c25 VD |
2306 | if (fail == CPUHP_INVALID) { |
2307 | st->fail = fail; | |
2308 | return count; | |
2309 | } | |
2310 | ||
33d4a5a7 ET |
2311 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2312 | return -EINVAL; | |
2313 | ||
1db49484 PZ |
2314 | /* |
2315 | * Cannot fail STARTING/DYING callbacks. | |
2316 | */ | |
2317 | if (cpuhp_is_atomic_state(fail)) | |
2318 | return -EINVAL; | |
2319 | ||
62f25069 VD |
2320 | /* |
2321 | * DEAD callbacks cannot fail... | |
2322 | * ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter | |
2323 | * triggering STARTING callbacks, a failure in this state would | |
2324 | * hinder rollback. | |
2325 | */ | |
2326 | if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU) | |
2327 | return -EINVAL; | |
2328 | ||
1db49484 PZ |
2329 | /* |
2330 | * Cannot fail anything that doesn't have callbacks. | |
2331 | */ | |
2332 | mutex_lock(&cpuhp_state_mutex); | |
2333 | sp = cpuhp_get_step(fail); | |
2334 | if (!sp->startup.single && !sp->teardown.single) | |
2335 | ret = -EINVAL; | |
2336 | mutex_unlock(&cpuhp_state_mutex); | |
2337 | if (ret) | |
2338 | return ret; | |
2339 | ||
2340 | st->fail = fail; | |
2341 | ||
2342 | return count; | |
2343 | } | |
2344 | ||
2345 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2346 | struct device_attribute *attr, char *buf) | |
2347 | { | |
2348 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2349 | ||
2350 | return sprintf(buf, "%d\n", st->fail); | |
2351 | } | |
2352 | ||
2353 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2354 | ||
98f8cdce TG |
2355 | static struct attribute *cpuhp_cpu_attrs[] = { |
2356 | &dev_attr_state.attr, | |
2357 | &dev_attr_target.attr, | |
1db49484 | 2358 | &dev_attr_fail.attr, |
98f8cdce TG |
2359 | NULL |
2360 | }; | |
2361 | ||
993647a2 | 2362 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2363 | .attrs = cpuhp_cpu_attrs, |
2364 | .name = "hotplug", | |
2365 | NULL | |
2366 | }; | |
2367 | ||
2368 | static ssize_t show_cpuhp_states(struct device *dev, | |
2369 | struct device_attribute *attr, char *buf) | |
2370 | { | |
2371 | ssize_t cur, res = 0; | |
2372 | int i; | |
2373 | ||
2374 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2375 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2376 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2377 | ||
2378 | if (sp->name) { | |
2379 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2380 | buf += cur; | |
2381 | res += cur; | |
2382 | } | |
2383 | } | |
2384 | mutex_unlock(&cpuhp_state_mutex); | |
2385 | return res; | |
2386 | } | |
2387 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2388 | ||
2389 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2390 | &dev_attr_states.attr, | |
2391 | NULL | |
2392 | }; | |
2393 | ||
993647a2 | 2394 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2395 | .attrs = cpuhp_cpu_root_attrs, |
2396 | .name = "hotplug", | |
2397 | NULL | |
2398 | }; | |
2399 | ||
05736e4a TG |
2400 | #ifdef CONFIG_HOTPLUG_SMT |
2401 | ||
05736e4a | 2402 | static ssize_t |
de7b77e5 JP |
2403 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2404 | const char *buf, size_t count) | |
05736e4a TG |
2405 | { |
2406 | int ctrlval, ret; | |
2407 | ||
2408 | if (sysfs_streq(buf, "on")) | |
2409 | ctrlval = CPU_SMT_ENABLED; | |
2410 | else if (sysfs_streq(buf, "off")) | |
2411 | ctrlval = CPU_SMT_DISABLED; | |
2412 | else if (sysfs_streq(buf, "forceoff")) | |
2413 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2414 | else | |
2415 | return -EINVAL; | |
2416 | ||
2417 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2418 | return -EPERM; | |
2419 | ||
2420 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2421 | return -ENODEV; | |
2422 | ||
2423 | ret = lock_device_hotplug_sysfs(); | |
2424 | if (ret) | |
2425 | return ret; | |
2426 | ||
2427 | if (ctrlval != cpu_smt_control) { | |
2428 | switch (ctrlval) { | |
2429 | case CPU_SMT_ENABLED: | |
215af549 | 2430 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2431 | break; |
2432 | case CPU_SMT_DISABLED: | |
2433 | case CPU_SMT_FORCE_DISABLED: | |
2434 | ret = cpuhp_smt_disable(ctrlval); | |
2435 | break; | |
2436 | } | |
2437 | } | |
2438 | ||
2439 | unlock_device_hotplug(); | |
2440 | return ret ? ret : count; | |
2441 | } | |
de7b77e5 JP |
2442 | |
2443 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2444 | static ssize_t | |
2445 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2446 | const char *buf, size_t count) | |
2447 | { | |
2448 | return -ENODEV; | |
2449 | } | |
2450 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2451 | ||
2452 | static const char *smt_states[] = { | |
2453 | [CPU_SMT_ENABLED] = "on", | |
2454 | [CPU_SMT_DISABLED] = "off", | |
2455 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2456 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2457 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2458 | }; | |
2459 | ||
2460 | static ssize_t | |
2461 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2462 | { | |
2463 | const char *state = smt_states[cpu_smt_control]; | |
2464 | ||
2465 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2466 | } | |
2467 | ||
2468 | static ssize_t | |
2469 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2470 | const char *buf, size_t count) | |
2471 | { | |
2472 | return __store_smt_control(dev, attr, buf, count); | |
2473 | } | |
05736e4a TG |
2474 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2475 | ||
2476 | static ssize_t | |
2477 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2478 | { | |
de7b77e5 | 2479 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2480 | } |
2481 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2482 | ||
2483 | static struct attribute *cpuhp_smt_attrs[] = { | |
2484 | &dev_attr_control.attr, | |
2485 | &dev_attr_active.attr, | |
2486 | NULL | |
2487 | }; | |
2488 | ||
2489 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2490 | .attrs = cpuhp_smt_attrs, | |
2491 | .name = "smt", | |
2492 | NULL | |
2493 | }; | |
2494 | ||
de7b77e5 | 2495 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2496 | { |
05736e4a TG |
2497 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2498 | &cpuhp_smt_attr_group); | |
2499 | } | |
2500 | ||
98f8cdce TG |
2501 | static int __init cpuhp_sysfs_init(void) |
2502 | { | |
2503 | int cpu, ret; | |
2504 | ||
de7b77e5 | 2505 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2506 | if (ret) |
2507 | return ret; | |
2508 | ||
98f8cdce TG |
2509 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2510 | &cpuhp_cpu_root_attr_group); | |
2511 | if (ret) | |
2512 | return ret; | |
2513 | ||
2514 | for_each_possible_cpu(cpu) { | |
2515 | struct device *dev = get_cpu_device(cpu); | |
2516 | ||
2517 | if (!dev) | |
2518 | continue; | |
2519 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2520 | if (ret) | |
2521 | return ret; | |
2522 | } | |
2523 | return 0; | |
2524 | } | |
2525 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2526 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2527 | |
e56b3bc7 LT |
2528 | /* |
2529 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2530 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2531 | * | |
e0b582ec | 2532 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2533 | * mask value that has a single bit set only. |
2534 | */ | |
b8d317d1 | 2535 | |
e56b3bc7 | 2536 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2537 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2538 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2539 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2540 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2541 | |
e56b3bc7 LT |
2542 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2543 | ||
2544 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2545 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2546 | #if BITS_PER_LONG > 32 | |
2547 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2548 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2549 | #endif |
2550 | }; | |
e56b3bc7 | 2551 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2552 | |
2553 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2554 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2555 | |
2556 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2557 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2558 | = {CPU_BITS_ALL}; |
b3199c02 | 2559 | #else |
4b804c85 | 2560 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2561 | #endif |
4b804c85 | 2562 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2563 | |
4b804c85 RV |
2564 | struct cpumask __cpu_online_mask __read_mostly; |
2565 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2566 | |
4b804c85 RV |
2567 | struct cpumask __cpu_present_mask __read_mostly; |
2568 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2569 | |
4b804c85 RV |
2570 | struct cpumask __cpu_active_mask __read_mostly; |
2571 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2572 | |
e40f74c5 PZ |
2573 | struct cpumask __cpu_dying_mask __read_mostly; |
2574 | EXPORT_SYMBOL(__cpu_dying_mask); | |
2575 | ||
0c09ab96 TG |
2576 | atomic_t __num_online_cpus __read_mostly; |
2577 | EXPORT_SYMBOL(__num_online_cpus); | |
2578 | ||
3fa41520 RR |
2579 | void init_cpu_present(const struct cpumask *src) |
2580 | { | |
c4c54dd1 | 2581 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2582 | } |
2583 | ||
2584 | void init_cpu_possible(const struct cpumask *src) | |
2585 | { | |
c4c54dd1 | 2586 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2587 | } |
2588 | ||
2589 | void init_cpu_online(const struct cpumask *src) | |
2590 | { | |
c4c54dd1 | 2591 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2592 | } |
cff7d378 | 2593 | |
0c09ab96 TG |
2594 | void set_cpu_online(unsigned int cpu, bool online) |
2595 | { | |
2596 | /* | |
2597 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2598 | * function by the reboot and kexec code which invoke it from | |
2599 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2600 | * regular CPU hotplug is properly serialized. | |
2601 | * | |
2602 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2603 | * does not protect readers which are not serialized against | |
2604 | * concurrent hotplug operations. | |
2605 | */ | |
2606 | if (online) { | |
2607 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2608 | atomic_inc(&__num_online_cpus); | |
2609 | } else { | |
2610 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2611 | atomic_dec(&__num_online_cpus); | |
2612 | } | |
2613 | } | |
2614 | ||
cff7d378 TG |
2615 | /* |
2616 | * Activate the first processor. | |
2617 | */ | |
2618 | void __init boot_cpu_init(void) | |
2619 | { | |
2620 | int cpu = smp_processor_id(); | |
2621 | ||
2622 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2623 | set_cpu_online(cpu, true); | |
2624 | set_cpu_active(cpu, true); | |
2625 | set_cpu_present(cpu, true); | |
2626 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2627 | |
2628 | #ifdef CONFIG_SMP | |
2629 | __boot_cpu_id = cpu; | |
2630 | #endif | |
cff7d378 TG |
2631 | } |
2632 | ||
2633 | /* | |
2634 | * Must be called _AFTER_ setting up the per_cpu areas | |
2635 | */ | |
b5b1404d | 2636 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2637 | { |
269777aa | 2638 | #ifdef CONFIG_SMP |
e797bda3 | 2639 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2640 | #endif |
0cc3cd21 | 2641 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2642 | } |
98af8452 | 2643 | |
731dc9df TH |
2644 | /* |
2645 | * These are used for a global "mitigations=" cmdline option for toggling | |
2646 | * optional CPU mitigations. | |
2647 | */ | |
2648 | enum cpu_mitigations { | |
2649 | CPU_MITIGATIONS_OFF, | |
2650 | CPU_MITIGATIONS_AUTO, | |
2651 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2652 | }; | |
2653 | ||
2654 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2655 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2656 | |
2657 | static int __init mitigations_parse_cmdline(char *arg) | |
2658 | { | |
2659 | if (!strcmp(arg, "off")) | |
2660 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2661 | else if (!strcmp(arg, "auto")) | |
2662 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2663 | else if (!strcmp(arg, "auto,nosmt")) | |
2664 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2665 | else |
2666 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2667 | arg); | |
98af8452 JP |
2668 | |
2669 | return 0; | |
2670 | } | |
2671 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2672 | |
2673 | /* mitigations=off */ | |
2674 | bool cpu_mitigations_off(void) | |
2675 | { | |
2676 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2677 | } | |
2678 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2679 | ||
2680 | /* mitigations=auto,nosmt */ | |
2681 | bool cpu_mitigations_auto_nosmt(void) | |
2682 | { | |
2683 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2684 | } | |
2685 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |